Re: [External] : Re: Shrinking the C core

[Arthur Miller]

Richard Stallman <rms@gnu.org> writes:

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>
> I implemented Common Lisp for the Lisp Machine in 1983.
> That included the generic sequence functions with their
> many keyword arguments.
>
> In 1984 I wrote Emacs Lisp and decided to omit all that.
> I have no regrets.  Their absence makes Emacs Lisp easier to use.

Thank you for explanation and clarficiation. Now at least I understand
why you don't like them.

> Keyword arguments are fine for an unusual, heavyweight operation such
> as creating a frame.  The sort of function whose doc you need to look
> up again each time you use it.  When something is as cumbersome as
> that, the question of how to pass the arguments is a pile of minor
> details that you'll see when you look it up.
>
> But it's a pain in the neck to make simple everyday functions such as
> `append' and `length' that cumbersome just for the sake of following a
> general system.  Part of this system is that the default argument
> values follow the system, rather than following the traditional Lisp
> functions -- so getting the traditional behavior requires actually
> specifying the keyword arguments to override defaults, almost every
> time.

Of course, but nobody suggests it is all-in. `length' is not a keyworded
in CL either. It would be madness to do something like naming all
arguments in all functions. But it is convenient to have keywords in
some places, like for example in define-minor-mode or make-process, or
even "new" define-keymap.

> Switching to Common Lisp would cause those painful incompatibilities.
> It is unacceptable.
>
> Defining the CL functions with a name prefix is ok, because the
> traditional Lisp functions are still available compatibly and we don't
> have to use the CL functions.  This is what we have now.

If cl-lib was loaded into the lisp image, we could even rename cl-defun
to defun, after we have initialized all the other stuff that goes into
the dump, and have "upgraded" vesion of defun and would be fully
compatible with traditional Lisp functions. We could even go further and
remove cl- prefix from bunch of symbols to make them less cumbersome to
use, and everything would stil be compatible with traditional Lisp
functions.

I think there is a thing that makes Lisp a bit special compared to other
programming languages, and Steel mentions it briefly in his legendary
talk: anyone can add a new feature to the language and it becomes part
of the vocabulary without distinction from the built-in stuff. Keyword
arguments does not require anything special from the C runtime, and we
see them pop-up in different forms in elisp. Perhaps elisp would be
better off to accept them and make cl-defun the norm, instead of seing
macros like define-minor-mode re-implement the technique and some other
macro possibly do something similar which leads to more less maintanable
code.

But that is just loud thinking, since my point wasn't to suggest any
changes, I just wanted to understand why you didn't like keyword
arguments per se, so thank you very much for the answer.